Computer apparatus have been widely employed in factories, business offices, and homes. With the use or the help of computer apparatus, it is possible to obtain the highest working efficiency, the optimal advertising effect, and the most convenient living conditions. Particularly, in recent years, the popularization of portable or notebook computer has brought even increased conveniences to users.
However, the portable or notebook computer is subject to undesirable falling due to poor working environment, user negligence, or improper use of the computer, which would adversely affect the normal operation of the portable computer and result in damage of precision devices in the computer, including the hard disk thereof, and data in the damaged hard disk would be destroyed. To protect the hard disk of a portable computer from damages in falling or violent vibration, some portable computers are incorporated with a falling sensor.
There are various techniques of prior art for detecting and protecting a computer from possible damage at falling. For example, Taiwan Utility Model No. M298215 discloses a storage device with power failure protection. The storage device includes a sensing unit for sensing a displacement of the device in at least one dimension; a processor coupled with the sensing unit for receiving the displacement and then outputting a control signal; a medium unit coupled with the processor for reading or setting data; and a switch respectively coupled with the processor and the medium unit for receiving the control signal to turn on or off power supplied to the medium unit.
U.S. Pat. No. 5,982,573 discloses a disk drive having a fall detection control system that detects when a disk drive is in a free fall, and takes precautionary protective action to minimize physical damage from any resulting shock upon impact. The disk drive includes an accelerometer device that measures acceleration of the disk drive along three mutually orthogonal axes x, y, and z and resolves the measurement into respective x, y, and z vectors. In a method disclosed in the prior art, to minimize shock-induced damage of the disk drive, the acceleration of the falling disk drive is detected; the detected acceleration is compared with a selected acceleration threshold level; a duration that the detected acceleration exceeds the acceleration threshold level is measured; the measured duration is compared with a selected reference time period; and a warning signal is output when the measured duration exceeds the reference time period. Upon receipt of the warning signal, a controller initiates protective routines in preparation for shock.
U.S. Pat. No. 5,227,929 discloses a protective reflex system for a portable computer hard disk. The portable computer hard disk protective reflex system includes a three axis accelerometer, a dedicated processor, and a central processing unit of the portable computer. The accelerometer detects changes in the acceleration of the portable computer and generates a signal to the dedicated processor, informing the dedicated processor to tell the central processing unit of the portable computer to park the disk heads.
U.S. Pat. No. 5,235,472 discloses an apparatus for sensing operating shock on a disk drive. The apparatus comprises a piezoelectric polymer film, an amplifier and a comparator. The piezoelectric polymer film is encapsulated and electrically shielded by a metallic or metallic coated package, for sensing shock loads generated by or applied to the disk drive and generating a voltage to the amplifier for amplification and then to the comparator for comparison with a predetermined threshold voltage. The control circuit accordingly issues a write fault signal when the detected signal exceeds the predetermined threshold voltage, to stop writing of the read/write heads. The device may be mounted on the computer disk drive of the unit in such a manner as to be at a 45 degree angle to each of the x, y and z axis of the orthogonal coordinate system so that linear and torsional forces may be monitored.
U.S. Pat. No. 5,333,138 discloses an apparatus and method for preventing data corruption in disk drives from mechanical shock during write operations. The apparatus comprises includes a mechanical shock sensor to sense mechanical shocks having a magnitude exceeding a predetermined threshold. When a mechanical shock is detected, a write disable circuitry interrupts the write current to the disk drive write head. A repositioning circuitry then repositions the data head over the original data track and the incomplete data that was interrupted by the mechanical shock is rewritten. The method disclosed in the prior art includes the steps of sensing a mechanical shock having a magnitude exceeding a predetermined threshold; storing information identifying the data being written at the onset of the sensed shock; interrupting the write current to the write head; repositioning the data head to the original track; and rewriting the data which was interrupted because of the sensed shock.
The falling sensor in U.S. Pat. No. 6,771,449 includes a tubular conductive member, a flexible member arranged inside the tubular conductive member, and a weight arranged to an edge of the beam. The weight contacts the conductive member at the deflected state (the normal state) of the flexible member, and the weight comes out of contact with the conductive member during a falling of the magnetic disk drive. On detecting the falling state, the drive activates an evacuating operation to evacuate the magnetic head by the unload mechanism. Therefore, demolitions of the magnetic head and the magnetic disk by a crush between the magnetic head and the magnetic disk, which is caused by a shock at the end of falling, can be avoided.
Further, a protection apparatus for hard disk drive unit of a portable computer is disclosed. The device senses the acceleration of the computer when the computer is in a free fall, and a control microprocessor of the disk drive unit determines that such state lasts for longer than a certain minimum of time. Upon these conditions being met, the control microprocessor signals the removal of the heads from the disk to park the heads.
However, these prior art techniques are usually uneasy to effectuate; some of them necessitate modification of an internal structure of the hard disk, while others require a special and specific processor to achieve the protection of the hard disk of a falling portable computer.